I'd appreciate some sort of audio cue when your energy is low. I always forget to check my meter, so I run out before I can go back to the surface and recharge, or I don't realize I don't have enough shots to get through this rock to the mineral I see.
Not a bad start! Could definitely develop into a full game. My main criticism is that W should also jump. Jumping with SPACE when using WSAD is always awkward. Also, arrows don't seem to consistently provide a jumping surface (though I did enjoy the way you did that part!). Finally, the score page has some text issues, as the score is misaligned. But if you fix the little things and expand it with more levels, it could certainly be something worth playing! Good job. :)
I love Fancy Pants. Great game so far! I found a glitch, though. In the first screen with water, I dove in and came up under the oil slide (on the left). I popped up out of the water and got stuck in the slide/wall in a permanent "falling" animation.